List non-inherited global variables

globals.js

;(function (root, doc) {
  'use strict'
  var element = doc.documentElement
    , iframe = doc.createElement('iframe')
    , globals = Object.keys(root)
  // Append iframe to the DOM
  element.appendChild(iframe)
  // Get inherited global variables
  var inherited = Object.keys(iframe.contentWindow)
  // Detach iframe
  element.removeChild(iframe)
  // Return non-inherited global variables
  return globals.filter(function(value){return inherited.indexOf(value) < 0})
}(this, this.document))